Acting as a motor for our body, thyroid hormones become even more essential during pregnancy. But according to a study, exposure to environmental pollutants, including three commonly used endocrine disruptors, could impact thyroid function and potentially have consequences for the fetus.
Located at the base of the neck, the thyroid gland mainly produces two hormones: triiodothyronine (or T3) and thyroxine (or T4). Necessary for the body to keep us in physical, intellectual or metabolic form, these thyroid hormones become even more essential at the time of pregnancy. They are particularly involved in the development of the fetus and a disruption can have consequences on the health of the unborn child.
According to a new study published in the journal Environmental Health Perspectives, exposure to chemical pollutants, and in particular molecules of the phenol, paraben and phthalate family, has an impact on the concentrations of thyroid hormones in pregnant women. A research consortium made up of researchers from Inserm, CNRS and the University of Grenoble Alpes carried out assays in the biological samples of 437 pregnant women, in order to establish a potential association between the presence of pollutants and thyroid hormone abnormalities. .
And several chemical pollutants were detected in the majority of participants, which confirms that they were almost all confronted with it and that more broadly, a majority of pregnant women are exposed to it on a daily basis. The main pollutants detected were known endocrine disruptors: propyl-paraben, bisphenol A and butyl-benzyl-phthalate. Since 2012, bisphenol A has been banned in containers intended for children under the age of three and a recent study confirmed that exposure to phthalates during pregnancy was responsible for an increase in the number of premature births.
What impact on the growth of children?
“Data from in vitro toxicological tests suggest that these pollutants may act on the mechanisms governing the synthesis and degradation of thyroid hormonessays Claire Philippat, Inserm researcher at the Institute for Advanced Biosciences (Inserm/CNRS/Grenoble Alpes University). Butyl-benzyl phthalate and bisphenol A could in particular inhibit the incorporation of iodine – an essential element for the synthesis of thyroid hormones – in thyroid cells.she adds.
“This work reinforces knowledge of the deleterious effects of exposure to certain chemical pollutants on thyroid function. They warn in particular about the frequent exposure of the population to these pollutants and invite to continue research on the consequences on the health of the child, because variations, even small, of the levels of thyroid hormones of the mother during pregnancy can impact the fetus and its development”she finishes.
Read also: Pregnancy and environmental impacts: 6 tips to limit the risks
Now that they have found that the majority of pregnant women are exposed to endocrine disruptors during pregnancy with an impact on thyroid hormone production, the research consortium’s next goal is to uncover the potential consequences of impaired thyroid function on neurodevelopment and growth in children.
Source :
- Phenol and phthalate effects on thyroid hormone levels during pregnancy: Relying on in-vitro assays and adverse outcome pathways to inform an epidemiological analysis, Environmental Health PerspectivesNovember 9, 2022